OBJECTIVE: To explore the pluripotential and possible clinical application of adult stem cells. METHODS: The original articles on adult stem cells were extensively reviewed and the recent advances were summed up. RESULTS: Adult stem cells were located at different tissues of human beings and had the pluripotentiality of self-renewal and differentiation. Some adult stem cells, such as in marrow, nerve, muscle, fat, skin, liver, tissues, had the ability to differentiate into the unrelated cell type. CONCLUSION: The pluripotential, ubiquitous distribution and plasticity of adult stem cells offered a new way in regeneration medicine, such as cell therapy and tissue engineering.
We have utilized the binocular flat and stereoscopic pattern to record visual evoked potentials (VEP) in normal and strabismic subjects. The aim was to find an electrophysiological correlation with the degree of binocular interaction in these subjects.The perception as tridimensional or flat derived from the disparity obtained with polaroid filters placed in front of the eyes. In normal subjects, the results demonstrated a significant increase of VEP amplitude during tridimensional perception of the pattern. In strabismic subjects the electrophysiological response were not correlated with the binocular conditions. The findings in the present study suggest that the binocular disparity in VEP examination is a useful technique and a better objective index for evaluating stereoscopic function than the psychophysical technique. （Chin J Ocul Fundus Dis,1992,8:10-13）
Objective To investigate the cell growth inhibition and apoptosis induced by rapamycin on human hepatocellular carcinoma Bel-7402 cells and to study the role of mitochondrium membrane potential in the process of apoptosis. Methods Bel-7402 cells in vitro were given 5, 10, 20, 30, 40 and 50 nmol/L different concentrations of rapamycin, and the cell growth inhibiting ratio of Bel-7402 was assessed by MTT assay. The changes of morphology of Bel-7402 were observed by Hoechst 33258 staining and flow cytometry (FCM), respectively; The cell mitochondrial membrane potential was detected by using JC-1 staining method. Results Rapamycin could inhibit the growth of Bel-7402 cells significantly by inducing apoptosis, and the growth suppression and the cell apoptosis both presented time-effect relationship and were also dose-dependent. The rates of inhibiting and cell apoptosis after 72 h exposure to 50 nmol/L rapamycin were significantly higher that those of other groups (P＜0.01). Typical morphological changes of cell apoptosis were observed very clearly after the Bel-7402 cells had been exposed to rapamycin for 48 hours using Hoechst 33258 staining method, and it was also observed that the mitochondrial membrane potential decreased when apoptosis occured (P＜0.01). Conclusion Rapamycin could inhibit the growth of Bel-7402 cells by inducing cell apoptosis, and the descent of mitochondrial membrane potential may play an important role in the process of cell apoptosis.
This paper discusses the relationship between stimulating pulse width and the threshold of electrically evoked compound action potential (ECAP). Firstly, the rheobase and chronaxy from strength-duration curve of nerve fiber was computed using the shepherd's experiment results. Secondly, based on the relationship between ECAP and the action potential of nerve fiber, a mathematical expression to describe the relationship between stimulating pulse width and ECAP threshold was proposed. Thirdly, the parameters were obtained and the feasibility was proved to the expression with the results of experiment using guinea pigs. Research result showed that with ECAP compared to the action potential of nerve fiber, their threshold function relationship with stimulating pulse width was similar, and rheobase from the former was an order smaller in the magnitude than the latter, but the chronaxy was close to each other. These findings may provide meaningful guidance to clinical ECAP measurement and studying speech processing strategies of cochlear implant.
Transcranial magneto-acoustic-electrical stimulation is a new non-invasive neuromodulation technology, in which the induced electric field generated by the coupling effect of ultrasound and static magnetic field are used to regulate the neural rhythm oscillation activity in the corresponding brain region. The purpose of this paper is to investigate the effects of transcranial magneto-acoustic-electrical stimulation on the information transfer and communication in neuronal clusters during memory. In the experiment, twenty healthy adult Wistar rats were randomly divided into a control group (five rats) and stimulation groups (fifteen rats). Transcranial magneto-acoustic-electrical stimulation of 0.05~0.15 T and 2.66~13.33 W/cm2 was applied to the rats in stimulation groups, and no stimulation was applied to the rats in the control group. The local field potentials signals in the prefrontal cortex of rats during the T-maze working memory tasks were acquired. Then the coupling differences between delta rhythm phase, theta rhythm phase and gamma rhythm amplitude of rats in different parameter stimulation groups and control group were compared. The experimental results showed that the coupling intensity of delta and gamma rhythm in stimulation groups was significantly lower than that in the control group (P<0.05), while the coupling intensity of theta and gamma rhythm was significantly higher than that in the control group (P<0.05). With the increase of stimulation parameters, the degree of coupling between delta and gamma rhythm showed a decreasing trend, while the degree of coupling between theta and gamma rhythm tended to increase. The preliminary results of this paper indicated that transcranial magneto-acoustic-electrical stimulation inhibited delta rhythmic neuronal activity and enhanced the oscillation of theta and gamma rhythm in the prefrontal cortex, thus promoted the exchange and transmission of information between neuronal clusters in different spatial scales. This lays the foundation for further exploring the mechanism of transcranial magneto-acoustic-electrical stimulation in regulating brain memory function.
Brain-computer interface (BCI) has high application value in the field of healthcare. However, in practical clinical applications, convenience and system performance should be considered in the use of BCI. Wearable BCIs are generally with high convenience, but their performance in real-life scenario needs to be evaluated. This study proposed a wearable steady-state visual evoked potential (SSVEP)-based BCI system equipped with a small-sized electroencephalogram (EEG) collector and a high-performance training-free decoding algorithm. Ten healthy subjects participated in the test of BCI system under simplified experimental preparation. The results showed that the average classification accuracy of this BCI was 94.10% for 40 targets, and there was no significant difference compared to the dataset collected under the laboratory condition. The system achieved a maximum information transfer rate (ITR) of 115.25 bit/min with 8-channel signal and 98.49 bit/min with 4-channel signal, indicating that the 4-channel solution can be used as an option for the few-channel BCI. Overall, this wearable SSVEP-BCI can achieve good performance in real-life scenario, which helps to promote BCI technology in clinical practice.
Objective To review the research progress of miRNA regulation in the differentiation of adipose-derived stem cells (ADSCs). Methods The recent literature associated with miRNAs and differentiation of ADSCs was reviewed. The regulatory mechanism was analyzed in detail and summarized. Results The results indicate that the expression of miRNAs changes during differentiation of ADSCs. In addition, miRNAs regulate the differentiation of ADSCs into adipocytes, osteoblasts, chondrocytes, neurons, and hepatocytes by regulating the signaling pathways involved in cell differentiation. Conclusion Through controlling the differentiation of ADSCs by miRNAs, the suitable seed cell for tissue engineering can be established. The review will provide a theoretical basis for molecular targeted therapy and stem cell therapy in clinic.
ObjectiveTo observe the changes of vision and visual evoked potentials (VEP) in patients with Leber hereditary optic neuropathy (LHON) before and after gene therapy.MethodsA retrospective cohort study. From December 2017 to October 2018, 35 cases of 70 eyes of m11778G.A/MT-ND4 mutant LHON patients who were diagnosed in the Tongji Hospital of Huazhong University of Science and Technology and received gene therapy were included in the study. There were 30 males (87.71%) and 5 females (12.29%), with the mean age of 23.31±6.72 years. The gene therapy method was intravitreal injection of rAAV2-ND4 (recombinant adeno-associated virus carrying NADH-ubiquinone oxidoreductase subunit 4 gene) into one eye. The eye with poor visual acuity was chosen as the injection eye. If both eyes had the same visual acuity, the right eye was designated as the injection eye. Seventy eyes were divided into the injected eye group and the non-injected eye group, in which were both 35 eyes. The best corrected visual acuity (BCVA) and pattern VEP (PVEP) examinations were performed in the injected eye group and the non-injected eye group before treatment (baseline), 1, 3, and 6 months after injection. Compare the changes of BCVA and PVEP between the injected eye group and the non-injected eye group at baseline, 1 month, 3 months, and 6 months after injection. Independent sample t test, paired sample t test or two independent sample nonparametric test were performed to compare the two groups.ResultsCompared with baseline, 1, 3, and 6 months after treatment, the BCVA of the injected eye group (t=3.530, 4.962, 5.281; P=0.001, 0.000, 0.000) and the non-injected eye group (t=3.288, 2.620, 2.252; P= 0.002, 0.013, 0.031) increased, and the difference was statistically significant; there was no statistically significant difference between VEP IT (tinjected eye group=?0.158, 1.046, ?1.134; Pinjected eye group = 0.875, 0.303, 0.190; tnon-injected eye group=0.773, ?0.607, ?0.944; Pnon-injected eye group= 0.445, 0.548, 0.352) and VEP A (Zinjected eye group=?0.504, ?0.934, ?1.065; Pinjected eye group= 0.614, 0.351, 0.287; Znon-injected eye group=?0.521, ?0.115, ?0.491; Pnon-injected eye group = 0.602, 0.909, 0.623).ConclusionAfter gene therapy, the visual acuity of the injected and non-injected eyes of LHON patients improved; PVEP did not change significantly, and remained stable compared with baseline.
Objective To observe the content of thromboxane (TXA2 ) and prostacyclin (PGI2) in optic nerves after forehead impact injury.Methods The right forehead zones of 32 rabbits were struck by biology impact machine. Tweenty-four rabbits that had afferent papillary defect after injury were chosen, and randomly divided into four groups: 1 day, 2, 4, and 7 days group. Right eyes were in the experimental group and left eyes were in the control group. Flash visual evoked potentials were examined before and after the traumatic injury. The rabbits ′eyes were removed, the optic nerves were pathologically examined, and the content of TXB2 and 6-Keto-PGF1αwhich were the products of TXA2 and PGI2 were assayed 1, 2, 4, and 7 days after traumatic injury respectively.Results Histopath ological examination revealed the findings of injuries of optic nerves of all the 24 rabbits. The latency of wave P1 was significantly delayed after traum atic injury (Plt;0.01), and amplitude of wave P1 was significantly decreased after traumatic injury (Plt;0.01). The content of TXB2 ［(172.35±26.52) pg/mg ］and 6-Keto-PGF1α［(161.78±24.83) pg/mg］were significantly higher in the injured optic nerves than in the uninjured ones 1 day after the traumatic injury (Plt;0.01). The rate of TXB2 /6-Keto-PGF1α (1.077±0.18) was significantly increased compared to the control group (Plt;0.05), and lasted to the 7th day.Conclusions The content of TXA2 and PGI2 significantly increases and the ratio of them is lopsided after forehead impact injury in rabbits. (Chin J Ocul Fundus Dis，2003，19：49-51)
Commonly clinical visual electrophysiological detection methods include flash ERG, pattern ERG, VEP and multifocal ERG, etc. These inspection methods play an important role in disease identification and visual function judgment. However, lacking of understand the basic principles of electrophysiological testing, misunderstandings of the clinician influence the choice of examination methods or interpretation of examination results. The understanding of the basic principles of electrophysiological testing and analysis of the causes of these misunderstandings have important clinical significance in the correct application of visual electrophysiological testing technology.